Biomedical subjects

J M Larner

Publications and source records attributed to J M Larner.

41 records · Page 3Linked to original sources

PubMed1977

A simple procedure for solubilizing 3beta-hydroxysteroid dehydrogenase from microsomes of rat adrenals and testis interstitial cells.

A simple procedure is described for solubilizing microsomal 3beta-hydroxysteroid dehydrogenase (3beta-HSD). Microsomes from rat adrenals or from testicular interstitial cells were incubated for 1 or 2 h at 0 C in a buffer containing NaCl followed by overnight storage at -20 C. Maximum solubilization of 3beta-hydroxy-5beta-androstan-17-one-HSD (androstane-3beta-HSD) was obtained by incubating adrenal microsomes with 1 M NaCl and interstitial cell microsomes with 2 M NaCl. Incubation with NaCl for 1 or 2 h resulted in maximum solubilization; incubation with NaCl for 4, 8 or 24 h did not change the amount of enzyme solubilized. From adrenal microsomes incubated with 1 M NaCl, up to 80% (105.7 millimicron/mg microsomes) of the total androstane-3beta-HSD activity was recovered in the supernatant following centrifugation at 130,000 x g for 1 h. The maximum amount of androstane-3beta-HSD solubilized from interstitial cell microsomes was 56% (29.5 millimicron/mg microsomes) at 2 M NaCl. The "solubilized" androstane-3beta-HSD was retarded when chromatographed on a Sephadex G-200 column and it did not pellet out when centrifuged at 130,000 x g for 15 h. KCL appeared to be equally effective in solubilizing androstane-3beta-HSD from microsomes. Other steroid dehydrogenase activities such as pregnanolone-HSD and 3beta-hydroxy-5alpha-androstan-17-one-HSD were also found in the 130,000 x g supernatant.

3-Hydroxysteroid Dehydrogenases↗

PubMedDate not supplied

Radiotherapy for basaloid squamous cell carcinoma of the head and neck.

Basaloid squamous cell carcinoma (BSCC) of the head and neck is a recently described high-grade variant of squamous cell carcinoma. It is a biologically virulent neoplasm with a propensity for nodal, as well as systemic, metastases. Because of the limited number of published reports, we reviewed data from patients of the University of Virginia Health Sciences Center and identified 16 cases of BSCC. The intent of this study was to determine the role of radiotherapy in the treatment of BSCC and better define the clinical features of this entity. Radiotherapy alone, or in combination with surgery, resulted in excellent local control rates. Distant metastases, chiefly pulmonary, occurred in more than half of the patients.

Carcinoma, Squamous Cell↗

PubMedDate not supplied

Definitive radiotherapy for T1 and T2 squamous cell carcinoma of the tonsil.

BACKGROUND: To assess whether survival or local control of early squamous cell carcinoma of the tonsil has been compromised by a moderate-dose approach. METHODS: Between 1970 and 1989, 185 patients with SCCa of the tonsil were seen at our institution. Fifty-three patients with T1 (30) and T2 (23) lesions treated with definitive radiotherapy were reviewed. Median follow-up was 60 months. The effects of total dose and site of the primary on survival and local regional control were analyzed. RESULTS: Three-year determinate survival was 77%. Mean total dose was 63.1 Gy. Site of the primary significantly affected survival (86% for fossa, 54% for pillars, p < 0.025). Local control at 2 years was 81% and was independent of dose > or = 63 Gy or site of the primary. Grade 4 complications defined by the RTOG/EORTC Acute Morbidity criteria occurred in three patients. CONCLUSIONS: Tumor doses on the order of 63 Gy or less result in excellent local control and survival rates for T1 and T2 carcinomas of the tonsil. Local control rates are better for fossa lesions than for pillar lesions.

Adult↗

PubMedDate not supplied

The tumor suppressor p53 can reduce stable transfection in the presence of irradiation.

The tumor suppressor p53 is believed to play an essential role in maintaining genome stability. Although it is currently unknown how p53 is involved in this important biological safeguard, several previous publications indicate that p53 can help to maintain genome integrity through the recombination-mediated DNA repair process. The integration of linearized plasmid DNA into the host chromosome utilizes the same repair process, and the frequency can be measured by clonogenic assays in which cells that were stably transfected by plasmid integration can be scored by their colony-forming abilities. To gain insight into whether p53 has a direct role in plasmid integration into the host chromosome, we determined the frequency of stable transfection with CHO cells expressing either wild-type or mutant p53 in the presence and absence of irradiation. We found that low-dose irradiation ( approximately 50 to 100 cGy) increased stable transfection frequencies in CHO cells regardless of their p53 status. However, the increase of transfection frequency was significantly lower in CHO cells expressing wild-type p53. Our data thus suggest that wild-type p53 can suppress plasmid DNA integration into the host genome. This p53 function may play a direct and significant role in maintaining genome stability.

Animals↗

PubMedDate not supplied

Extradural failure in glioblastoma multiforme: MRI demonstration.

Glioblastoma multiforme is invariably associated with intracranial failure following conventional therapy. Extracranial as well as metastatic failure are rarely seen. Subtle extracranial abnormalities in most patients with glioblastoma multiforme are not indicative of convexity failure. However, in patients with high p53 and Ki67 immunoreactivity and in whom the dura was not closed at the time of craniotomy, the possibility of early extradural failure should be considered.

Adult↗